The present invention is related to novel molecularly imprinted polymers, and in particular to improvements in the production of molecularly imprinted polymers (MIPs), as well as to these specific MIPs, and to the use of MIPs for specific applications. The MIPs of the present invention are particularly suitable for binding to, and thereby removing, toxins in the gastrointestinal tract. As an exemplary implementation, the present invention is described with regard to the removal of bile acids and bile salts from the gastrointestinal tract. In addition, the present invention is also useful for treatment of various diseases which are related to, and/or characterized by an effect of, bile acids and bile salts, such as atherosclerosis, cancer, liver disease and various diseases of the gastrointestinal tract. The MIP compounds of the present invention are also useful for combination therapy with other medications. These medications may involve mechanisms of action that lower or change the composition of bile acids and salts in the body or by a different mechanism. In addition the present invention also is useful for the diagnosis and monitoring of various diseases by selectively binding to an established marker which is then identified using known binding indicator techniques such as fluorescence. As an illustrative example for implementation, the present invention is described with regard to the diagnosis of medical conditions which are related to, and or characterized by an effect of, bile acids and/or bile salts, such as atherosclerosis, various diseases of the gastrointestinal tract, cancer and inflammatory conditions. This is achieved by determining the level of at least one specific bile acid or salt or the ratio of at least one specific bile acid or to at least a second specific bile acid or salt and determining whether these levels fall within an establish range which indicates the potential existence of the relevant disease. The analysis is performed on bile acids and or bile salts found in serum, bile, gastric contents, and feces.
The subject of molecularly imprinted polymers has been extensively reviewed (e.g., G. Wulff, Angew. Chem., Int. Ed. Engl. 1995, 34, 1812-1832; A. G. Mayyes and K. Mosbach, Trends Anal. Chem. 1997, 16, 321-332; E. N. Vulfson, C. Alexander, and M. J. Whitcombe Chem. Brit. 1997, 33, 23-26; K. Haupt and K. Mosbach, Trends Biotechnol. 1998, 16, 468-475; Molecular and Ionic Recognition with Imprinted Polymers, ACS Symp. Ser. 703; R. A. Bartsch and M. Maeda, Eds.; American Chemical Society, Washington, D.C., 1998) and a number of patents on this topic have been issued [e.g., U.S. Pat. No. 4,127,730 (Wulff, G., Sarhan A.); U.S. Pat. No. 5,110,833 (Mosbach. K.); U.S. Pat. No. 5,630,978 (Domb, A.,); U.S. Pat. No. 5,587,273 (Yan, M. et al.); U.S. Pat. No. 5,872,198 (Mosbach, K. et al;)]. A schematic depiction of the formation of MIPs for deoxycholic acid (DCA) and glycodeoxycholic acid (GDCA) is shown in FIGS. 1A and 1B. Although the binding/recognition site is actually a family of non-homogeneous sites, the scheme illustrates how the cavities for two similar substances may differ.
The synthesis of MIPs, including those described with regard to the present invention in the xe2x80x9cDescription of the Preferred Embodimentsxe2x80x9d below, is performed with functional monomers. The monomers which were used for the present invention include all of the monomers listed in the following section. The synthesis of these monomers and related derivatives and analogs can be performed by organic chemists of ordinary skill in the art. It should be noted that although the present invention is described with regard to MIPs which bind bile acids and bile salts, this is for the purposes of description only and is not intended to be limiting in any way.
Bile Acid Sequestrants.
A number of polymers, such as cholestyramine, are used as bile acid sequestrants. Their action is based on the presence of strongly basic groups in the polymer (typically, ion exchange resin type of polymers) and they are used for cholesterol lowering and bile-related diseases. These materials are limited because they have limited potency and they also remove (bind) other required substances such as nutrients, drugs, etc. In addition, they often irritate the bowel and are not convenient or palatable to the patient. Accordingly there is a need for improved bile sequestrants. Selective MIPs which bind bile acids and salts do not remove needed nutrients, drugs or other substances and will be more potent; they will have low or no bowel irritation and have improved dosages. Importantly, the MIPs can be made so that they are selective to the more hydrophobic bile acids such as deoxycholic acid. Research shows that the more hydrophobic bile acids inhibit the removal of LDL from the blood stream and lead to a higher cholesterol blood serum level (Hueman, D. M. et al., J Lipid Res. 30: 1161, 1989).
While bile acids and salts serve important functions in the body, such as promoting digestion of fat, researchers have found that the more hydrophobic (water-resistant) bile acids, such as deoxycholic acid (DCA), chenodeoxycholic acid (CDCA) and lithocholic acid (LCA) facilitate higher absorption of lipids such as cholesterol and fats into the blood stream and are toxic, causing damage to cells and promoting cancer. Current research indicates that these more hydrophobic bile acids are highly significant disease-causing agents.
Additionally, research has implicated specific bile acids and bile salts as contributing to a number of diseases. For example, DCA has been implicated in the following:
Gallstones (Low-Beer, T. S., et al., Lancet (1978) 2:1063-65
Colorectal cancer (Ochsenkuhn, T. et al., American Cancer Society (1999) 1664-69; Hylemon P., Journal of Lipid Research (1997); Bernstein C. et al., Cancer Research (1999) 59, 2353-2357.)
Barrett""s esophaghus and erosive esophagitis (Nehre D et al., Gut, (1999) 44(5) 598-602; Kauer et al., Surgery, (1997) 122(5) 874-81)
Arteriosclerosis caused by the presence of Oxidized LDL (Fuhrman B et al., Free Radic Biol Med 34-461997).
Inflammatory conditions promoted by the presence of COX-2 (Zhang et al., J Biol Chem (1998) 273(4):2424-8).
Clearly, improved compounds such as MIPS are required with both higher and more specific binding capacity to these particular bile acids and bile salts. Furthernore, such MIPs would be useful for the treatment and/or prevention of diseases which are at least partially caused by, or otherwise related to, these specific bile acids and/or salts. Unfortunately, such MIPs are not currently available.
illustrative example
The background art neither teaches nor suggests MIPs with both higher and more specific binding capacity for particular bile acids and/or salts, for the treatment and/or prevention of diseases which are at least partially caused by, or otherwise related to, specific bile acids and/or salts.
The present invention is of improved MIPs with both higher and more specific binding capacity, including the synthesis of such MILPs, the compounds themselves, and specific applications thereof. The MIP compounds of the present invention have the advantage of being adaptable for specific targeted therapeutic and diagnostic uses and/or functionality, thereby enabling treatment and diagnosis to be more effectively performed.
As an example of a particularly preferred specific application of these compounds, the present invention encompasses the use of MIPs as sequestrants in the gastrointestinal tract, particularly in order to bind and therefore remove toxins from the gastrointestinal tract.
As a particularly preferred example of such toxins, the compounds of the present invention are useful for the binding and removal of specific bile acids and/or salts. Examples of such bile acids and/or salts include, but are not limited to, a bile acid such as deoxycholic acid (DCA) or the tauro- or glyco-conjugates of DCA. The bile acid or bile conjugate is optionally chenodeoxycholic acid (CDCA) and the glyco or tauro conjugates thereof, or lithocholic acid (LCA) and the glyco or tauro conjugates thereof.
These bile acids and salts are targeted for removal because of their role in various disease states. For example, although bile acids and salts serve important functions in the body, such as promoting digestion of fat, more hydrophobic (water-resistant) bile acids, such as DCA, CDCA and LCA, facilitate higher absorption of lipids such as cholesterol and fats into the blood stream and are toxic, causing damage to cells and promoting cancer. Therefore, these more hydrophobic bile acids are highly significant disease-causing agents.
The novel molecularly imprinted polymers (MIPs) of the present invention are able to specifically target and remove significant proportions of these more hydrophobic bile acids. At present there is no drug that selectively targets the removal of hydrophobic bile acids from the body.
The present invention also encompasses the use of these MIP compounds for the treatment and/or prevention of diseases which are at least partially caused by, or otherwise related to, specific bile acids and/or salts. Examples of such diseases include, but are not limited to, heart disease, particularly by lowering cholesterol levels; treatment of heart and other oxidized LDL-initiated diseases such as cancer and inflammatory conditions by lowering oxidized LDL; cholesterol-related gallstones; colorectal cancer and its precursors; inflammatory disease initiated by the presence of Cox-2, gastro-esophageal reflux diseases (GERD) including Barrett""s esophagus, corrosive esophagitis, and esophageal cancer. In addition, the present invention encompasses the use of such compounds to concurrently treat and/or prevent two or more of the above diseases.
The present invention also encompasses use of the MIP medication in combination with other medications where there is a need for more effective treatment which cannot be achieved by the MIP medication alone. These medications may involve mechanisms of action that lower or change the composition of bile acids and/or salts in the body or by a different mechanism.
The present invention also encompasses the use of the compounds of this invention for diagnosis and monitoring of compounds by binding to a marker and using known binding indicator techniques such as fluorescence. The analysis is performed on samples taken from the body. In a particularly preferred example, the compounds of the present invention are useful for the diagnosis and monitoring of specific bile acids and salts. Examples of such bile acids and salts include, but are not limited to, a bile acid such as deoxycholic acid (DCA) or the tauro- or glyco-conjugates of DCA. The bile acid or bile conjugate is optionally chenodeoxycholic acid (CDCA) and the glyco or tauro conjugates thereof, or lithocholic acid (LCA) and the glyco or tauro conjugates thereof.
These bile acids and salts may be targeted for diagnosis and monitoring because of their roles in various disease states. For example, although bile acids serve important functions in the body, such as promoting digestion of fat, more hydrophobic (water-resistant) bile acids, such as DCA, CDCA and LCA, are toxic, causing damage to cells and promoting cancer. Therefore, these more hydrophobic bile acids are highly significant disease-causing agents.
The novel molecularly imprinted polymers (MIPs) of the present invention are able to specifically bind these hydrophobic bile acids, and then to be detected by using known binding indicator techniques such as fluorescence, for thereby quantifying the levels of the more hydrophobic bile acids.
The present invention also encompasses the use of these MIP compounds for the monitoring and diagnosis of diseases which are at least partially caused by, or otherwise related to, specific bile acids and/or salts. Examples of such diseases include, but are not limited to, colorectal cancer and its precursors; and esophageal diseases including Barrett""s esophagus, erosive esophagitis, and esophageal cancer by monitoring the levels of at least one bile acid or salts or the ratios of at least one bile acid or salts to other bile acids and/or salts.
The present invention solves a number of long-felt needs. There is a need for more effective medication, for example, with patients who do not respond to conventional treatment, and/or have severe conditions for which the currently available medication is insufficient for the required treatment. This may be achieved with the use of MIP therapy, alone or optionally in combination with other medication. The use of combination therapy is well established. These optional, additional medications may operate according to mechanisms of action that lower or change the composition of bile acids and/or salts in the body or by a different mechanism.
There is the need for simple screening techniques for diagnosis and monitoring, especially for asymptomatic conditions. An illustrative example is treatment of cancer where the earlier diagnosis of the cancer or pre-cancerous condition can significantly impact on the success of treatment and also contribute to preventing the condition. In some cases there is need for improving and simplifying existing methods; in others no existing method exists. MIPs have been used for the diagnosis and monitoring of various diseases by selectively binding to an established marker which is then identified using known binding indicator techniques such as fluorescence. In many cases there will be a need for the improved MIPs to achieve the required sensitivity.
As an example for implementation, the present invention is described with regard to the use of MIPs for diagnosis of medical conditions which are related to, and or characterized by, an effect of bile acids and/or bile salts, such as atherosclerosis, various diseases of the gastrointestinal tract, cancer and inflammatory conditions. This is achieved by determining the level of at least one specific bile acid or the ratio of at least one specific bile acid to at least a second specific bile acid and determining whether these levels fall within an establish range which indicates the potential existence of the relevant disease. The analysis is performed on bile acids and or bile salts found in serum, bile, gastric contents, and feces.
Hereinafter, the term xe2x80x9ctreatmentxe2x80x9d or xe2x80x9ctreatxe2x80x9d for a disease state also includes the prevention of the occurrence of one or more symptoms and/or effects of the disease state itself. Hereinafter, the term xe2x80x9cbile acidxe2x80x9d includes both conjugated and unconjugated bile acids unless otherwise indicated.